PB2071: INTRALESIONAL RITUXIMAB IN THE TREATMENT OF PRIMARY CUTANEOUS B-CELL LYMPHOMA
Authors: M. Callejas Charavia, L. Castilla García, J. Aspa, P. García Ramírez, M. Argüello Marina, C. Martínez Vázquez
Journal: HemaSphere (2022)

Background: Cutaneous B-cell lymphomas can be classified into two categories: primary cutaneous lymphomas (PCL) and secondary lymphomas. PCL are restricted to skin infiltration and are indolent. The two most prevalent PCL subtypes are primary cutaneous marginal zone lymphomas (PCMZL) and primary cutaneous follicle center lymphomas (PCFCL). The first line treatment recommended both by EORTC and ISCL, is surgery (excisional biopsy) associated or not to local radiotherapy. Nevertheless, these recommendations are based on retrospective studies including few patients. There is a lack of randomized clinical studies comparing the different available therapies for primary cutaneous lymphomas. Among the alternative therapies to the classical first line of treatment, the guideliness of EORTC and ISCL consider the use of intralesional rituximab. The advantages of this treatment are its tolerability, absence of secondary aesthetic effects, accessibility, and easy administration. On the contrary, radiotherapy is less accessible in certain hospitals and presents a greater incidence of secondary cutaneous adverse effects. It causes both acute and chronic reactions, such as alopecia, erythema, peeling, hyperpigmentation and, in cases of repeated doses, even ulceration. Similarly, the need for appropriate margins of excision in surgical procedures entails a more aggressive approach with worse esthetic results that can even lead to infection or ulceration, and it also requires more resources, both material and human. Aims: To present our experience in the management of PCL. Methods: Out of a total of 30 patients diagnosed between April 2009 and June 2018, 14 patients (46,7%) were treated with intralesional rituximab, 15 with the standard therapies, and 1 with both. We evaluated treatment efficacy, security, and tolerability of both approaches. Treatment response was assessed following our own criteria which categorizes the response as: complete (100% of skin bleaching), partial (50-99% size reduction), stable disease (<25% increase to <50% decrease in size of the treated injuries), and progression (> 25% increase of the treated injuries). The rituximab dosing schedule was 10mg/injury (intralesional) or 10-40 mg in the case of PCFCL, 3 times per week, for one week. If the lesion persists, the dose can be repeated, until it disappears. Results: Both groups of patients were demographically comparable. The median age of patients was 60 years (interquartile range: 49-75 years). 52% were women. The median number of injuries was 1. The most frequent locations were the face (41%, including the frontal region, jaw and temple) followed by the back (14%). In the group treated with rituximab, the median PFS was 75 months (ICR: 38,6-99 months) (with a median follow-up of 86 months). As the only adverse effect, 3 patients showed a flu-like reaction the day after the injection without need of hospital assistance. Two patients (14%) suffered from a relapse of the skin lesions and were retreated with intralesional rituximab achieving CR. One of the patients showed persistent lesions after 3 doses, reaching CR after the sixth dose. In the standard of care group, the median PFS and median follow up were both 118 months. Ten patients (67%) presented adverse effects related with local radiotherapy. Image:Summary/Conclusion: In our experience, intralesional rituximab is a safe, accessible, and effective therapeutic option. Therefore, we consider that it should be included as a first line treatment at the same level as the classic alternatives, especially in cases where the esthetic consequences of the treatment are particularly relevant.